Talking-machine needle.



J. E. & W. B. SULLIVAN.

TALKING MACHINE NEEDLE.

APPLICATION FILED SEPT. 11, 1907.

918,389. Patented Apr. 13, 1909.

wwwtow UNITED STATES PATENT OFFICE.

JOHN E. SULLIVAN, OF READING, AND WILLIAM B. SULLIVAN, OF PHILADELPHIA, PENNSYLVANIA.

TALKING-MACHINE NEEDLE.

Specification of Letters Patent.

Patented April 13, 1909.

Application filed September 11, 1907. Serial No. 892,269.

have invented certain new and useful Im-' proyements in Talking-Machine Needles, of which the following is a specification.

Our invention relates generally to phono gra hs or talking machines, and more particu arly to unimproved form of stylus or needle for engaging the wave-line groove of the record; the main object being to insure a uniformly accurate reproduction of the sounds by which said record was originally produced, while at the same time preventing deterioration of the record by the action of the needle upon the finely lined groove thereof, suchas ordinarily rapidly occurs. I The invention is fully described in connection with the accompan drawing and the novel features are specifica y pointed out in the claim.

The drawing is a fragmentary crosssectional view of a talking machine record showing the groove thereof greatlyenlarged and with my im roved st 'lus or needle ened therein, t e latter eingcorrespondmg y enlarged.

. it is confined.

. Owing to the extreme nicety with which the delicately defined groove of the record must be followed by the needle of the reproducing mechanism in order thatthe finest recorded vibrations may be accurately reroduced, great .difliculty has' been heretoore experienced. This is dueito the minute but practically serious wear of the needle and groove which results from their frictional contact throughout thelong and devious course of the record-groove, and to the modification of the original sounds which ordinarigy result from a scratchy action of the nee e in following the sinuous path to which The object of our invention is to eliminate these defects, and this object we have found to be practically attained 'b forming the needle as indicated in magn' ed dimensions in the drawing.

-A indicatesia record disk, having a spiral groove 1) as usual, corresponding in its sinuo'sities with the vibrations imparted to the recording diaphragm by the recorded sounds and 0 indicates our improved needle with its point engaged in said groove; a showing of these arts only of a sound recording and repro ucing machine being required to illustrate our invention, and such parts being enlarged, as previously stated, so as to make clear the distinguishing features of form and proportions.

To enable the invention to be utilized with thirty-seconds of an Inch in len th. The

oint f of the tip e, which is ma 0 slightly lunt as indicated, has a diameter of two one-thousandths (.002) of an inch, and the incline g of the ta ered tip, instead of being straight, is inwar ly curved or concaved longitudinally as shown, to 'a radius of about three inches, so that the diameter. .at the blunted point is very gradually increased at first and thereafter more rapidly as it extends into the round body 11. The improved effect of this novel shape of record-needle tip is very marked, both in the securing of more accurate reproductions ofthe exact original sounds free from the unpleasin tones commonly introduced in the reproduction; and in the avoidance of wearing action u on'the record whereby its usefulness is or arily soon destroyed or impaired. The point f so rests in the bottom of the groove 6 as to greatly reduce friction and scratch while at the same time accurately followin the delicate deflections of the groove; and the relative diameters and lengths of the sothe tones because of undue yieldin in the needles'tructure. Notwithstandingt ehardness of the needle material there has been heretofore not only the objectionable scratch referred to, but such wear of the sharp needle oint durin its contact with What we claim is r the very lengt y groove 0 many records, as The talldng machine needle described to frequently cause quite imperfect reprocomprising a body and a'concavely tapered duction of the latter portion; which effect is point. '15 5 avoided in my improved needle by the fact In testimony whereof, We affix our signathat the point f is not only slightly blunted tures, in the presence of two witnesses.

originally but that it is so slightly changed JOHN E. SULLIVAN. in diameter by wear, owing to the con- WILLIAM B. SULLIVAN. caved conical form of the tip, as to have I Witnesses:

10 no appreciable efiect upon the proper repro- D. M. STEWART, ductlon of the whole record. i V W. G. STEWART. 

